The objective of the proposed research is to develop technology for producing prosthetic assemblies of microchannels that can be utilized in artificial organs. These microchannels, with diameters of 10 to 20 microns, are imbedded in a matrix material with nanoscale pores. The microchannel assemblies somewhat simulate physiologic capillary beds. Mass transfer to/from blood flowing in such assemblies will be greatly enhanced compared to that with current technology. Although possibly applicable to a variety of organ-function replacement devices, the overall specific aim of the current proposal is to develop the technology for artificial lungs. Effective artificial lungs could have a significant clinical impact as a bridge to lung transplantation, as a support device immediately post lung transplant, and as a rescue and/or supplement to mechanical ventilation during treatment of severe respiratory failure. Preliminary calculations suggest that a 250 ml volume artificial lung using 12 mu m microchannel wafers for gas exchange could process 4 I/min blood using air. The basic component of these microchannel assemblies for artificial lungs will be wafers of porous, biocompatible matrix containing microchannels. We propose to produce sample wafers of this basic component and conduct a series of gas transfer studies to determine the dependence of transport efficiency on blood flow rate, gas-side oxygen concentration, microchannel diameter and length, and wafer matrix material. We also propose to investigate methods to improve the production of these wafers using different fiber and matrix materials and by varying the preparation procedure. Our proposed technique involves (1) making an array of closely spaced fibers as template for the microchannels, (2) imbedding the fiber bundle in a porous matrix, (3) removing the fibers, thereby creating an array of microchannels within the porous matrix wafer, (4) machining the wafer to a desired shape, (5) coating the external faces with a thin but dense nonporous film, and (6) coating the microchannel walls and wafer surfaces with silicone rubber for biocompatibility. We have successfully demonstrated steps (1) to (3), and produced small samples of 12 mu m diameter channels in a wafer. The results of the proposed study will provide proof of concept that such microchannel devices are substantially superior to the conventional devices. Future work would include detailed blood compatibility tests and address scale-up issues.